silverhill seed in south africa has certainly stocked g. sutherlanidii seed and may very well have the other species as well---check their website (you can find their web address thru a "google" search)to find out for sure, they are very nice people to work with!!!! i grew mine from their seed and had no problems with germination (they are alledged to be easy to start from cuttings as well).

Thank you -- they have all three species!